1. Field of the Invention
The present invention relates to a method and apparatus to control a set paper in an image forming device. More particularly, when a user operates a printer driver or a panel of the image forming device to set a type of paper which is not coincident with a paper which is actually fed, that is, the user makes a print instruction by selecting a type of paper unsupportable by a cassette, the invention generates a warning message to inform the user of the unsuitable type of paper. The invention also sets a new type of paper or converts the set type of paper into a suitable type of paper so that an image can be formed on a new paper or a suitable paper.
2. Description of the Related Art
In general, electrophotography is widely used in an image forming device such as a copying machine, a Laser Beam Printer (LBP) and a plain paper facsimile. As well known in the art, the electrophotogrphy includes electrification, exposure, development, transference and fixing.
FIG. 1 schematically illustrates an engine mechanism in an electrophotographic image forming device utilizing contact electrification.
The contact electrification as show in FIG. 1 is generally used to minimize ozone generation induced from electrification, in which a conductive roller or brush functioning as a contact-electrifying body is contacted with a photoconductive drum to form a predetermined level of surface potential on the photoconductive drum. In particular, FIG. 1 illustrates the conductive roller which is utilized in contact electrification.
As shown in FIG. 1, an engine driving motor (not shown), functioning as a main motor of an engine, turns the photosensitive drum 10 clockwise, as indicated with an arrow, corresponding to process operations which are executed by an electrophotographic processor.
First, electrification uses a charge roller 12 or a contact charger to form uniform electric charge on the photosensitive drum 10. The charge roller 12 has a negative potential owing to a negative charging voltage or VCH.
The photosensitive drum 10 is charged through contact with the charge roller 12 to have a negative surface potential, which is typically approximately −800V. In these circumstances, feed rollers 30 and 32 feed a paper from a paper cassette (not shown) toward a developing unit of an apparatus body.
Second, in an exposure operation, the charged photosensitive drum 10 is exposed to light corresponding to a draft or an image data to form an electrostatic latent image thereon, in which a Laser Scanning Unit (LSU) 14 is used to selectively expose a portion of the photosensitive drum 10 corresponding to an image area to be printed, so as to form the electrostatic latent image thereon. Because the exposed portion of the photosensitive drum 10 changes its surface potential but the remaining portion of the photosensitive drum, which is not exposed to light, maintains the surface potential, the electrostatic latent image is formed with a potential difference between the exposed and un-exposed portions of the photosensitive drum 10.
Third, in a development operation, developer is attached to the electrostatic latent image on the photosensitive drum 10 to convert the latent image into a visible image. That is, a developing roller 16 is typically applied with a developing bias voltage VD of about −450V to have a negative potential so that the developer is coated on the developing roller 16. A doctor blade (not shown) regulates the quantity of developer so that the developer is uniformly coated on the developing roller 16. Then, developer having a negative potential is partially moved from developing areas to the exposed regions of the photosensitive drum 10 under potential difference so that developer attached to the photosensitive drum 10 converts the latent image into the visible image.
Fourth, developer is transferred from the photosensitive drum 10 to the paper by a transfer roller 18. The transfer roller 18 is applied with a transfer voltage Vt of about +800 to +1500V so that developer is transferred to the paper from the photosensitive drum 10.
Fifth, in a fixing operation, after transference of developer, the paper passes between a hot heat roller 20 and a high pressure roller 22 so that melted toner is fixed to the paper. Upon completion of fixing toner to the paper, the image forming device discharges the paper to complete a single copying or printing process with respect to the paper.
Hereinafter an image forming device having such an engine mechanism of the prior art will be described in brief with reference with FIG. 2.
FIG. 2 is a block diagram schematically illustrating an image forming device. As shown in FIG. 2, the image forming device comprises a host interface 100, a memory 110, a control panel 120, a controller 130, an engine interface 140, an engine controller 150 and a printer engine 160. The host interface 100 interfaces signals and data communicated between a host such as a personal computer or PC and the controller 130. The memory 110 stores application programs executed by the controller 130, associated information and a variety of data which are generated in response to execution of the control 130. The control panel 120 includes, for example, a key input to allow a user to input various instructions (e.g., type of paper setting, initialization and reset) into the image forming device and a display to provide various information to the user. The engine interface 140 interfaces signals and data communicated between the controller 130 and the engine controller 150. The engine controller 150 controls the printer engine 160 in response to various signals and data which are provided through the engine interface 140 from the controller 130. That is, when the controller 130 inputs a print instruction according to a set type of paper, the engine controller 150 determines transfer temperature and high pressure values according to the set type of paper and provides the determined values to the printer engine 160. The printer engine 160 carries out electrification, exposure, development, transference and fixation according to the set type of paper by using data from the engine controller 150 in order to perform paper printing.
Hereinafter a paper printing method of the image forming device having the above construction will be described in order of operation with reference to FIGS. 2 and 3.
FIG. 3 is a flow chart schematically illustrating a process of controlling a set paper in an image forming device of the prior art.
First, a user sets the type of a paper to be printed in 101. That is, as the user sets the type of the paper to be printed via a printer driver of the personal computer, a paper-setting data is provided to the controller 130 via the host interface 100. Alternatively, if the user sets the type of paper to be printed by using the control panel 120 of the image forming device, the paper-setting data is also provided to the controller 130.
The controller 130 receives the paper-setting data inputted via the host interface 100 or the control panel 120, and provides the paper-setting data to the engine controller 150 via the engine interface 140.
The engine controller 150 recognizes the paper-setting data provided via the engine interface 140 from the controller 130, and determines a fixing temperature corresponding to the set type of paper and a voltage of a high voltage unit to fix an image on the paper in 102.
The values of fixing temperature and voltage are provided to the printer engine 160, which prints the corresponding paper based upon the values provided from the engine controller 150 in 104.
That is, if the user selects an automatic feed mode instead of designating a specific feeder at the time of setting the type of paper to be printed via operation of the printer driver of the personal computer or the control panel 120 of the image forming device itself, a paper is fed by the cassette containing papers according to the priority of feeders.
Since there is no information about a set feeder to feed the paper in the case of the automatic feed mode, all types of papers supported by the image forming device may be set. However, an automatic feeder in the form of a cassette may not feed some types of papers. For example, the cassette type feeder may not support an envelope or a card since it is too thick to be fed by the cassette. In this circumstance, toner formed on the envelope or the card is fixed at a temperature which is higher than that of a plain paper. Also, a high voltage to form the image on the paper is also different according to the type of paper.
Accordingly, if the plain paper is loaded in the cassette and the envelope or a card is erroneously set, unsuitably high values of temperature and voltage are applied to the plain paper to degrade the quality of an image. Furthermore, since the image forming device is operated at the high temperature, a fixing unit can be damaged if used for a long time period.